OBJECTIVE: To establish finite element models of different preserved angles of osteonecrosis of the femoral head (ONFH) for the biomechanical analysis, and to provide mechanical evidence for predicting the risk of ONFH collapse with anterior preserved angle (APA) and lateral preserved angle (LPA). METHODS: A healthy adult was selected as the study object, and the CT data of the left femoral head was acquired and imported into Mimics 21.0 software to reconstruct a complete proximal femur model and construct 3 models of necrotic area with equal volume and different morphology, all models were imported into Solidworks 2022 software to construct 21 finite element models of ONFH with LPA of 45°, 50°, 55°, 60°, 65°, 70°, and 75° when APA was 45°, respectively, and 21 finite element models of ONFH with APA of 45°, 50°, 55°, 60°, 65°, 70°, 75° when LPA was 45°, respectively. According to the physiological load condition of the femoral head, the distal femur was completely fixed, and a force with an angle of 25°, downward direction, and a magnitude of 3.5 times the subject's body mass was applied to the weight-bearing area of the femoral head surface. The maximum Von Mises stress of the surface of the femoral head and the necrotic area and the maximum displacement of the weight-bearing area of the femoral head were calculated and observed by Abaqus 2021 software. RESULTS: The finite element models of ONFH were basically consistent with biomechanics of ONFH. Under the same loading condition, there was stress concentration around the necrotic area in the 42 ONFH models with different preserved angles composed of 3 necrotic areas with equal volume and different morphology. When APA was 60°, the maximum Von Mises stress of the surface of the femoral head and the necrotic area and the maximum displacement of the weight-bearing area of the femoral head of the ONFH models with LPA<60° were significantly higher than those of the models with LPA≥60° ( P<0.05); there was no significant difference in each index among the ONFH models with LPA≥60° ( P>0.05). When LPA was 60°, each index of the ONFH models with APA<60° were significantly higher than those of the models with APA≥60° ( P<0.05); there was no significant difference in each index among the ONFH models with APA≥60° ( P>0.05). CONCLUSION From the perspective of biomechanics, when a preserved angle of ONFH is less than its critical value, the stress concentration phenomenon in the femoral head is more pronounced, suggesting that the necrotic femoral head may have a higher risk of collapse in this state.
Adult ; Humans ; Femur Head/surgery* ; Finite Element Analysis ; Stress, Mechanical ; Femur/diagnostic imaging* ; Femur Head Necrosis/surgery*

OBJECTIVE: To analysis and determine MR signs of Harris score ARCO stages 2-4 in osteonecrosis of femoral head (ONFH). METHODS: Thirty-four patients with ONFH of ARCO stages 2 to 4 who underwent routine MR, T2 mapping, 3D-SPACE sequence examination and Harris score were retrospectively collected from January 2019 to June 2020, and 3 patients were excluded, and 31 patients were finally included, including 23 males and 8 females, aged from 18 to 62 years old with an average of(40.0±10.8) years old. Among them 21 patients with bilateral femoral head necrosis, totally 52 cases, including 17 with ARCO stage 2 patients, 24 ARCO stage 3, and 11 ARCO stage 4. MR imaging signs (femoral head collapse depth, ONFH index, bone marrow edema, hyperplasia, grade and T2 value of cartilage injury, and joint effusion) were scored and measured on the picture archiving and communication system (PACS) workstation, and the cartilage quantitative parameter T2 value was calculated and measured on Siemens postprocessing workstation. Pearson correlation analysis was used to evaluate the correlation between various MR signs and Harris score, and then multiple linear regression analysis was used to examine impact of MR signs on Harris hip score. RESULTS: Femoral head collapse depth(r=-0.563, P=0.000), grade of cartilage injury(r=-0.500, P=0.000), and joint effusion (r=-0.535, P=0.000) were negatively correlated with Harris score by Pearson correlation analysis. Multiple linear regression analysis showed that joint effusion(β=-6.198, P=0.001) and femoral head collapse depth(β=-4.085, P=0.014) had a significant negative impact on Harris hip score. CONCLUSION Femoral head collapse depth and joint effusion both had significant negative relationship with Harris hip score. It is recommended to routinely evaluate femoral head collapse depth and joint effusion quantitatively and gradedly, so as to efficiently and accurately assist clinical diagnosis and treatment.
Male ; Female ; Humans ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Femur Head Necrosis/diagnostic imaging* ; Retrospective Studies ; Femur Head/diagnostic imaging* ; Bone Transplantation/methods* ; Magnetic Resonance Imaging ; Treatment Outcome

BACKGROUNDOsteonecrosis of the femoral head (ONFH) is the result of dysfunctional blood supply, but associations between specific damaged arteries, imaging changes and clinical sign require more understanding. We investigated characteristics of ONFH that pertain to blood supply, imaging appearance, and clinical feature to judge the prognosis of ONFH.

METHODSClinical data were collected for 92 patients (118 hips) with ONFH, including gender, age, duration of pain (from initial clinical presentation to arthroplasty), cause, stage, and classification. Magmatic resonance imaging and X-rays were obtained of all patients to diagnose ONFH. The sizes of lesions were classified by necrotic index. The location of necrosis was classified as Type A, B, or C using the grading system by magmatic resonance imaging and X-rays. All hips were imaged with digital subtraction angiography to visualize their blood-supply characteristics. Hips were divided into groups based on the source artery for femoral head damage: superior retinacular artery (S), inferior retinacular artery (I), and combined superior and inferior retinacular arteries (S+I). Via digital subtraction angiography, imaging appearances and clinical data in three groups were compared.

RESULTSONFH was caused by damage in either the superior or inferior retinacular artery, or both, in all of 118 hips. The group with only inferior retinacular artery damage reported longer hip pain duration than the other groups. The probability of the lesion extending laterally to the acetabular edge in group S was much more than it in group I. Necrosis indices of the patients in S and S+I were higher than those in group I.

CONCLUSIONSONFH associated with interruption of the superior and inferior retinacular arteries in this study. When the former alone was damaged, the necrosis of the volume was larger, the risk of femoral head collapse was higher and the time from initial clinical presentation to arthroplasty was shorter.

Adult ; Aged ; Angiography, Digital Subtraction ; Female ; Femur Head ; diagnostic imaging ; Femur Head Necrosis ; diagnostic imaging ; Humans ; Male ; Middle Aged ; Young Adult

OBJECTIVE: To compare computer measurement semi automatic quantitative detection software system with ultra thin layer pathological section to confirm the avascular necrosis percentage of the femoral head, and provide reference for clinical treatment options. METHODS: From June 2012 to December 2013, the X-ray and MRI of 24 patients(24 hips on unilateral) were reviewed, who had avascular necrosis of the femoral head at late stage (stage III and IV) according to the ARCO international staging system, and performed by total hip arthroplasty. There were 15 males and 9 females, with an average age of (65.1±8.8) years old ranging 33 to 74 years old. Based on imaging system combined with computer aided technology(CAD) system and postoperative ultrathin slice, the volume of the area of femoral head necrosis were calculated. Then combining with the total volume of the femoral head was calculated by X-ray, the percentage of each femoral head necrosis area was calculated as a percentage of the whole ball head in both methods. RESULTS: For 24 hips, the normal femoral head volume was (39.58±3.29) cm³ on average of X-ray film, the necrotic volume was (20.00±3.04) cm³ on average of MRI by the calculation of computer. The necrotic volume occupying in the volume of the normal femoral head was (42.92±6.09)% on average ranged. The necrotic lesion size was larger than 40% in 16 hips, 30% to 40% in 8 hips, 1 ess than 30% in 0 hip. Under the pathological section, the necrosis volume was (19.89±3.17) cm³, the necrotic volume occupying in the volume of the normal femoral head was (40.33±6.36)%. The necrotic lesion size was larger than 40% in 12 hips, 30% to 40% in 11 hips, 1 ess than 30% in 1 hip. In computer and general measurement, the two entire femoral head volume difference was (0.113±0.466) cm³, there was no significant difference using these measurements(=-1.186, =0.248). After the linear correlation statistics analysis, there was a positive correlation relationship in necrotic volume between computer software and pathology measurement(γ=0.980, =0.000). CONCLUSIONS The severity of the necrotic femoral head is closely related to the percentage of necrotic area. When the ratio of necrotic lesions and the whole femoral head is greater than 30%, the patients' clinical symptoms tend to aggravate, the probability of total hip arthroplasty increased significantly. It have great significances in femoral head necrosis installment, judge the prognosis, guide the selection of treatment and monitoring curative effect.
Adult ; Aged ; Arthroplasty, Replacement, Hip ; Female ; Femur ; Femur Head ; Femur Head Necrosis ; diagnostic imaging ; Follow-Up Studies ; Hip ; Humans ; Male ; Middle Aged

OBJECTIVETo study the cause of X-ray misdiagnosis of the avascular femur head necrosis, so as to reduce the misdiagnosis rate and raise the early diagnosis level.

METHODSThe clinical and X-ray data of 99 patients(123 hips) with avascular femur head necrosis diagnosed by MRI were analyzed retrospectively. Among the patients, 56 patients were male and 43 patients were female,ranging in age from 21 to 84 years old,with an average of 53 years old. The patients had symptoms such as hip pain,functional restriction in flexion, adduction, abduction and internal rotation,and some patients had limping. The duration of the disease ranged from 1 week to 2 years.

RESULTSAmong 99 patients(123 hips),46 patients(52 hips) was misdiagnosed by the X-ray, the misdiagnosis rate was 42.27%, 100.00% in 0 stage, 100.00% in I stage, 83.67% in II stage, 18.18% in II stage, 0.00% in IV stage, 0.00% in V stage; the X-ray stage was negatively correlated with the rate of misdiagnosis. The careless film-reading and invigorating large enterprises while relaxing control over small ones was the main reason of misdiagnosis,then the lack of clinical histories and low-quality of X-ray projection.

CONCLUSIONThe relevant clinical history and comprehensive careful film-reading is the key to reduce the rate of misdiagnosis.

Adult ; Aged ; Aged, 80 and over ; Diagnostic Errors ; Female ; Femur Head Necrosis ; diagnostic imaging ; Humans ; Male ; Middle Aged ; Radiography ; X-Rays

By discussing different ways on prediction, prevention and treatment of femur head necrosis (FHN), to provide a theory reference for future clinical application. By searching, reading and summarizing related-literatures through CNKI, VIP, CBM and foreign-related literature, to sum up the relevance methods and techniques of currently used. It was found that imaging study (especially X-ray and MRI) was of great importance in prediction. There were several ways (both non-surgical or surgical) for prevention and treatment. FHN collapse was affected by many factors, but most of the researches were all focus on one aspect of the mechanism and based on small samples. It is necessary to have a research with a large sample and to compare the effect on different treatment. Early and effective imaging inspection is needed for high risk group of FHN; possibility of collapse should be predicted for existing FHN; core decompression or vascularized bone grafting are required for collapse of high risk group. Early prediction and treatment are essential for FHN patients.
Bone Transplantation ; Decompression, Surgical ; Femur Head Necrosis ; complications ; diagnostic imaging ; surgery ; Humans ; Magnetic Resonance Imaging ; Tomography, X-Ray Computed

OBJECTIVE: To establish a risk assessment and prediction system for early osteonecrosis of the femoral head (ONFH) in order to predict the collapse risk. METHODS: The risk assessment system for early necrosis and collapse of femoral head was established based on the combination of Steinberg stage, ABC typing and the proportion of the proximal sclerotic rim. Firstly, Steinberg stage system was applied. ABC typing was applied to predict risk in stage I, type C was risk free, type B was low risk, type A and type BC were medium risk, type A-C and type AB were high risk. The classification of proximal sclerotic rim was first applied when the Steinberg stage was Ⅱ-Ⅲ, and type 2 was expected to be low risk. If the classification of proximal sclerotic rimwas type 1, then the ABC typing was applied, type C was risk-free, type B was low risk, type A and type BC were medium risk, type A-C and type AB were high risk. According to this prediction system, the collapse risk of femoral head in 188 cases(301 hips) were predicted by retrospective analysis. All the hips were enrolled at the out-patient department of orthopedic in Guang'anmen Hospital attached to China Academy of Chinese Medical Science. The consistency of the prediction results of three doctors and one doctor at different times were evaluated. RESULTS: Among them, 136 cases were male, 52 were female. 75 cases were single hip, 113 were double hip. The age of the patients wa 19 to 64(42.61±12.07) years. The natural course of disease was 0.33 to 5.00(3.62±1.93) years. 206 hips in 301 hips had collapsed, with a collapse rate of 68.44%. In the risk-free group, none hip had collapsed, with a collapse rate of 0%. In the low-risk group, 9 hip in 91 hips had collapsed, with a collapse rate of 9.89%. In the medium-risk group, 12 hip in 19 hips had collapsed, with a collapse rate of 63.16%. And in the high risk group, 185 hips in 190 hips had collapsed, with a collapse rate of 97.37%. They were significantly differences in their collapse rate ( CONCLUSION The risk assessment and prediction system for early ONFH selects different methods to predict the risk of collapse according to the imaging characteristics of different stages, which is combines with the comprehensive assessment of multiple risk factors. The system is applicable to a wide range, simple operation and convenient for clinical application.
Adult ; China ; Female ; Femur Head/diagnostic imaging* ; Femur Head Necrosis/epidemiology* ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Risk Assessment ; Treatment Outcome ; Young Adult

Adult ; Female ; Femur Head Necrosis ; diagnostic imaging ; Fibromyalgia ; etiology ; Humans ; Severe Acute Respiratory Syndrome ; complications ; Tomography, Emission-Computed, Single-Photon

OBJECTIVETo evaluate the clinical value of radionuclide bone scintigraphy in diagnosis of avascular osteonecrosis in patients with severe acute respiratory syndrome (SARS) in convalescence.

METHODSWe performed three-phase bone scintigraphy of femoral head regions and whole-body bone scan in SARS patients 4-6 months after they recovered from the syndrome, and then compared the results with simultaneous MRI.

RESULTSTypical avascular necrosis at different stages and severities was found on bone scintigraphy at 31 femoral heads of 16 SARS patients, 97% of which were MRI positive. Suspicious necrosis was found at 42 femoral heads of 23 patients, 67% of which were MRI negative. Among 30 patients with normal three-phase scintigraphic results, 10% of whom were suspicious on MRI. In addition, abnormal distributions of radioactivity were observed in other bones on the whole-body bone scans of 29 patients, including osteonecrosis of knees in 15 patients.

CONCLUSIONSRadionuclide bone scintigraphy is valuable in early diagnosis of osteonecrosis in SARS patients in convalescence. It provides a mutually supplementary tool for MRI.

Adolescent ; Adult ; Convalescence ; Female ; Femur Head Necrosis ; diagnostic imaging ; pathology ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Osteonecrosis ; diagnostic imaging ; pathology ; Radionuclide Imaging ; Severe Acute Respiratory Syndrome ; diagnostic imaging ; pathology ; physiopathology ; Young Adult

Based on the unilateral CT images of a clinical patient in stage III for avascular necrosis of femoral head, three-dimensional finite element models of proximal femur are established, including normal model, necrosis model and prothetic model. Based on the same set of CT images, the material properties are assigned to the three finite element models respectively. Finally, the process of bone grafting for avascular necrosis of femoral head is simulated with finite element analysis. The results indicate that when the necrosis parts of femoral head are removed, the stress and displacement of proximal femur increase accordingly, and after the surgical operation of bone grafting, the stress and displacement of proximal femur can decrease effectively and become closer to the normal state. All the results indicate that the bone grafting operation is effective and reliable.
Bone Transplantation ; methods ; Computer Simulation ; Femur Head Necrosis ; diagnostic imaging ; surgery ; Finite Element Analysis ; Humans ; Imaging, Three-Dimensional ; Models, Biological ; Tomography, X-Ray Computed